JPH0353499B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field] The present invention relates to a fluid actuated device for a frictional engagement device for a transmission.

[Prior Art] As a fluid actuation device (hydraulic servo mechanism) for a friction engagement device (multi-disc clutch, multi-disc brake, belt brake, etc.) used in a vehicle automatic transmission, etc., the friction engagement device is released. A fluid pressure servo motor using a two-stage (double) piston on the side is known (Japanese Patent Publication No. 46-20769).

[Problem to be Solved] However, in the above-mentioned servo motor, pressure oil is supplied to the two stages of pistons from separate oil passages, and the formation of the oil passages has the disadvantage that the hydraulic control circuit is complicated.

An object of the present invention is to provide a fluid operating device for a frictional engagement device for a transmission that can simultaneously supply pressure oil to two-stage pistons with the simplest configuration.

[Means for Solving the Problems] In order to achieve the above object, a fluid operating device of the present invention has the following configuration.

In order to achieve a predetermined drive ratio between the input shaft and the output shaft of the transmission, a frictional coupling is used that engages each element of the gear system or solidifies one of the elements to a fixed member. In the fluid operating device of the transmission device, in order to engage or disengage the cylinder 2 provided in the case 202 of the transmission and the frictional engagement device arranged inside the case 202, the frictional engagement device is inserted from inside the cylinder 2. a first piston 5 connected to the pressing member and slidably disposed within the cylinder 2;
provided on one side of the first piston 5 inside,
a second oil chamber 14 that applies pressure oil to the first piston 5 in a direction in which the pressing member engages the frictional engagement device;
a first oil chamber 11 that is provided on the other side of the piston 5 and applies pressure oil to the first piston 5 in a direction that causes the pressing member to release the frictional engagement device;
It is fitted and fixed to the other side of the first piston 5 in the cylinder 2, and the first piston 5 side is slidably fitted to a small annular projection 52 formed at the center of the first piston 5. a second piston 6 connected to the pressing member and slidably disposed within the large inner diameter portion of the sleeve 3;
A third oil chamber 17 is provided in the second piston 6 and extends through the first piston 5 and a third oil chamber 17 arranged to apply pressure oil in a direction that causes the pressing member to release the frictional engagement device. The third oil chamber 17 and the first
A fluid operating device for a frictional engagement device for a transmission, comprising a flow path 54 communicating with an oil chamber 11.

[Operation and Effects of the Invention] The first piston 5 side has a third oil chamber 17 and a first annular projection 52 formed at the center of the first piston 5.
Since the flow path 54 is formed to communicate with the oil chamber 11, the structure can be avoided from complicating the structure and increasing costs.
Pressure oil can be supplied to two pistons at the same time.

Further, the inside of the sleeve 3 has a small inner diameter portion that is slidably fitted into a small annular projection 52 formed at the center of the first piston 5, and a second piston 6 is slidably disposed. Since there are two stages with a large inner diameter, the difference in pressure receiving area between the release side and the engagement side can be easily and freely adjusted by changing the inner diameter dimension.

[Example] Next, the present invention will be explained based on an example shown in the drawings.

FIG. 1 is a sectional view showing an embodiment of a fluid actuated device of a frictional engagement device for a transmission according to the present invention and a frictional engagement device for a transmission operated by the fluid actuated device.

In this embodiment, the frictional engagement device for a transmission is a band brake 50, and its fluid actuation device is a hydraulic servo mechanism 1.

The handbrake 50 includes a belt-shaped friction band 50.
1 surrounds the outer circumference of a predetermined rotary transmission drum 201 in the transmission 200, a metal fitting 502 fixed to one end thereof is fixed to the transmission case 202, and a pressurized metal fitting 503 is attached to the other end. is fixed.

The hydraulic servo mechanism 1 includes a cylinder 2 and a sleeve 3 fitted into the cylinder 2 and serving as a piston guide. Inside the cylinder 2 and sleeve 3 are a first piston 5 and a second piston 6.
A two-stage piston 4 consisting of a piston rod 7 and a piston rod 7 is fitted into the pressurized metal fitting 503 and the second-stage piston 4.
Activate the press rod 8 disposed between the The two-stage piston 4 is provided with a return spring 9 and a locking spring 10 that elastically locks the press rod 8 .

Note that the pressing member of the present invention is composed of a piston rod 7 and a pressing rod 8 in this embodiment.

Cylinder 2 is transmission case 20
It is integrally formed with the outer wall 102 of No. 2, and has a three-stage inner diameter consisting of a small diameter portion 21, a medium diameter portion 22, and a large diameter portion 23 that increase sequentially from the tip side (left end side in the figure). Further, in the cylinder 2, an axial hole 25 in which the press rod 8 slides is formed in the tip wall 24, and an opening 26 at the rear end is covered with a flange plate 27. Furthermore, from the large diameter part 23 to the middle diameter part 22 of the cylinder 2,
A cylindrical sleeve 3 is fitted therein, the diameter of which increases stepwise from the distal end side, forming three stages on the outside and two stages on the inside.

The distal end side 31 of the sleeve 3 is a thick annular wall projecting inward, and forms a small-diameter cylinder portion 32 located in the middle of the cylinder 2 in the axial direction. Further, the rear end side 33 of the sleeve 3 forms a large diameter cylinder portion 34 on which the second piston 6 slides.

The first piston 5 has a shaft hole 5a, a flange plate 51 that is slidably fitted into the middle diameter part 22 of the cylinder is provided at the middle part, and a small diameter cylinder part of the sleeve 3 at the rear end. 32 is provided with a small annular projection 52 that is slidably fitted therein. This first
The shaft hole 5a of the piston 5 is coaxial with the center of the cylinder 2, and the piston rod 7 is slidably inserted therethrough. The first piston 5 also has a front surface 53 of the flange plate 51 from the rear end surface of the annular small protrusion 52.
A flow path 54 is provided that penetrates the.

The second piston 6 is provided with a flange plate 61 at the rear end of a cylindrical body having a shaft hole 60, which is slidably fitted into the large-diameter cylinder portion 34 of the sleeve 3. This second piston 6 is similar to the first piston 5.
The piston rod 7 is slidably inserted into the shaft hole 60, and is prevented from moving in the rearward direction by a snap spring 71 attached to the rear end of the piston rod 7. .

At the tip of the piston rod 7, a press rod 8 is arranged in series and slidably fits into the hole 25 of the cylinder 2. This press rod 8 has a tapered tip end 81 that contacts the locking fitting of the band brake 50, and a small diameter flange plate 82 is provided at the rear end, and an axial hole 83 is formed. A tip 72 of the piston rod 7 is slidably fitted into the piston rod 7 .

A locking spring 10 is installed between the small-diameter flange plate 82 and the flange plate 51 of the first piston 5 to press the press rod 8 forward (to the left in the figure) against the second-stage piston 4. . Further, a return spring 9 is installed between the tip wall 24 of the cylinder 2 and the flange plate 51.

A first oil chamber 11 is formed between the tip wall 24 of the cylinder 2 and the flange plate 51 of the first piston 5, and communicates with an oil passage 13 provided in the cylinder 2 via an oil port 12.

The second oil chamber 1 is located between the flange plate 51 of the first piston 5 and the thick annular wall (tip side) 31 of the sleeve.
4, and the cylinder 2 is connected through the oil port 15.
It is connected to an oil passage 16 provided in the.

An annular wall (tip side) 31 and a second
A third oil chamber 17 is formed between the piston 6 and the piston 6.
The third oil chamber 17 is connected to the first oil chamber 1 through the flow path 54.
I am contacting 1.

Further, the chamber between the second piston 6 and the flange plate 27 is open to the atmosphere via a port 19.

Next, the effect will be explained.

The hydraulic servo mechanism 1 engages or opens the band brake 50 by selectively supplying and discharging the hydraulic pressure of the hydraulic control device (not shown) of the automatic transmission to the oil passage 13 or the oil passage 16. Brake mechanism B1 is activated.

When hydraulic pressure is supplied to the oil passage 13 and pressure is discharged from the oil passage 16, pressure oil is supplied to the first oil chamber 11, and then from the flow passage 54 to the third oil chamber 17. . As a result, both the first piston 5 and the second piston 6 are urged rearward (leftward in the figure),
Due to the action of hydraulic pressure and return spring 9, the first
Piston 5, second piston 6 and piston rod 7
is set at the position shown in FIG. At this time, the pressing rod 8 is urged rearward (rightward in the figure) by the pressurized metal fitting 503 by the return force of the friction band 501, compressing the locking spring 10 and setting it at the position shown in FIG. As a result, the brake mechanism B1 is smoothly released even at a relatively low hydraulic pressure due to the large effective pressure receiving area of the two-stage piston 4. Furthermore, the first oil chamber 11 and the third oil chamber 17 are
Since some time lag occurs in the supply of pressure oil, the brake mechanism B1 is released smoothly.

When the hydraulic pressure is supplied to the oil passage 16 and the oil passage 13 is discharged, the first piston 5 moves forward ( After the tip of the first piston 5 contacts the small diameter flange plate 82, the return spring 9 is further compressed to push the press rod 8, and the pressurized metal fitting 503 is deflected to the left in the figure. friction band 5
01 to the rotating transmission drum 201. This allows the brake to be smoothly engaged.

In this way, the first piston 5 is placed on the brake release side.
The reason for using the two-stage piston 4 on which the second piston 6 acts simultaneously is to increase the difference in effective pressure-receiving area between the brake release side and the brake engagement side without increasing the body size. In this embodiment, the effective pressure receiving surface of the first oil chamber 11 and the third oil chamber 17, which are the brake release side oil chambers, is relative to the effective pressure receiving surface of the second oil chamber 14, which is the brake engagement side oil chamber. It is set to about 3 times. As a result, while the engagement hydraulic pressure P1 of the brake mechanism B1 supplied from the oil passage 16 to the second oil chamber 14 is introduced, the engagement pressure P2 of the other frictional engagement element is lower than the engagement hydraulic pressure P1. from the oil passage 13 to the first oil chamber 11 and the third oil chamber
Even under the operating conditions in which oil is supplied to the oil chamber 17, the brake mechanism B
1 is opened smoothly.

As described above, in the fluid operating device of the frictional engagement device for a transmission according to the present invention, the flow path 54 that communicates the first oil chamber 11 and the third oil chamber 17 is provided in the first piston 5. Therefore, a two-stage piston 4 with a large effective pressure-receiving area can be obtained with a simple configuration without complicating the hydraulic circuit or increasing the size.

Further, since the sleeve 3 forms the small diameter cylinder part 32 and the large diameter cylinder part 34, the difference in area between the release side and the engagement side can be adjusted freely and over a wide range by changing the inner diameters of these parts.

In the above embodiment, the oil passage 16 and the second oil chamber 1
4, the fourth oil chamber 18 is evacuated, and only the first piston 51 is operated.
As another embodiment, the oil passage 16 and the fourth oil chamber 18 may be communicated with each other, the second oil chamber 14 may be evacuated, and only the second piston 61 may act.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a fluid actuated device of a frictional engagement device for a transmission according to the present invention. In the figure, 1...hydraulic servo mechanism (fluid actuated device),
2... Cylinder, 3... Sleeve, 4... Two-stage piston, 5... First piston, 6... Second piston, 7...
Piston rod, 8... Pressing rod, 11... First oil chamber, 14
...Second oil chamber, 17...Third oil chamber, 52...Annular small protrusion of first piston, 54...Flow path.

Claims (1)

[Claims] 1. In order to achieve a predetermined drive ratio between the input shaft and the output shaft of the transmission, each element of the gear device is engaged, or any of the elements is attached to a fixed member. In a fluid actuated device of a frictional engagement device that is solidified, the above-mentioned method is used to engage or disengage the cylinder 2 provided in the case 202 of the transmission and the frictional engagement device disposed within the case 202. cylinder 2
a pressing member 8 disposed across the frictional engagement device from inside; a first piston 5 connected to the pressing member and slidably disposed within the cylinder 2; a second oil chamber provided on one side of the first piston and configured to apply pressure oil to the first piston in a direction that causes the pressing member to engage the frictional engagement device; a first oil chamber that is provided on the other side of the first piston and applies pressure oil to the first piston in a direction that causes the pressing member to release the frictional engagement device; A sleeve having a small inner diameter that is fitted into and fixed to the other side of the first piston, and the first piston side is slidably fitted into a small annular projection 52 formed at the center of the first piston. 3; a second piston connected to the pressing member and slidably disposed within the large inner diameter portion of the sleeve; A third oil chamber arranged to apply pressure oil in the direction of release, and a flow path 54 provided through the first piston and communicating the third oil chamber and the first oil chamber. A fluid actuation device for a frictional engagement device for a transmission.